Q: My son died a year ago. Can I give his wife (my ex daughterinlaw) fidya money?
A: If she is deserving of zakah, she can also be eligible for fidya.

Kindly also see if she has the amount of nisab. If she does not own the amount of nisab, she will definitely qualify for fidya and zakah.

May Allah (SWT) make her matters easy, ameen

Allah Certainly Knows Best.